Ischeamic cerebrovascual accidents can be caused by full or partial occlusion of the brain's arterial blood vessels, for example by intracranial thrombi or emboli, or by thrombi in the dural venous sinuses that drain blood from the brain.
The removal of occluding bodies from the cerebral vasculature may be achieved by pharmacological means, for example by thrombolysis, or by mechanical means, for example by physically breaking a thrombus or embolus into a number of pieces prior to its removal.
The breaking into pieces of an occluding body can be deleterious as dislodged parts may travel through the cerebral vasculature and subsequently form emboli themselves. Blocking and/or suction means are therefore required to ensure that dislodged parts are safely collected. The need for blocking and/or suction means limits the size of vessels in which such an approach can be employed and precludes its application for many of the small and tortuous intracranial blood vessels, for example the branch vessels of the circle of Willis or middle cerebral artery, and arteries arising from the distal vertebral and basilar arteries.